A wafer acceptable test (WAT) refers to using probes to feed testing signals into a testing structure of a wafer, and then using a feedback signal analysis to understand electrical properties of the wafer, thereby determining if the wafer has defects appearing during fabrication. In the WAT, a probe card is used to simultaneously test plural chips on the wafer. The probe card includes plural probes corresponding to plural testing pads on the wafer, in which the testing pads are connected to plural devices under test (DUTs) on the wafer. With the increasing chip integrity, contact areas between the tips of the probes and the testing pads are greatly shrunk, the affecting the WAT results.